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In 1990 the NASA spacecraft Voyager 1, careening across the solar system on its way to becoming the most distant human-made object in space, took a glimpse back at the planet it had left 13 years earlier. Six billion kilometers away, Earth was barely distinguishable against the backdrop of space—a "pale blue dot," as astronomer Carl Sagan would famously dub it.

Earlier this month another interplanetary explorer caught a striking glimpse of Earth, this one captured as the spacecraft, a European probe called Rosetta, approached our planet from deep space. In a third and final flyby of Earth, Rosetta tapped the planet's gravity to adjust its own trajectory for a planned encounter with a comet in 2014. As the probe drew nearer to its home planet, just a sliver of Earth was visible, but the flyby nonetheless revealed striking detail—a swirl of clouds above Antarctica is discernible, as is highly reflective ice near the South Pole.

For decades, missions to the moon and beyond have revealed Earth in brand-new visual contexts, as a pale blue dot or a richly textured marble of many colors.